Log in to personalise your experience and connect with IOP.

Video transcript of Episode 14: Snowball Slingshot

Below is the full transcript of Episode 14: Snowball Slingshot delivered by IOP's Imogen Small.


On-screen text reads: "Do Try This at Home from the Institute of Physics. Episode 14: Snowball Slingshot".

Introductory music plays. A video recording shows two people, Imogen and Sam, playing a game of snowball slingshot in their back garden. Imogen successfully launches a tin foil snowball into a crate several metres away from them. Imogen gasps and Sam mutters.

Camera cuts to Imogen sitting behind a table.

Imogen: "Hello! Welcome to Do Try This at Home brought to you by the Institute of Physics. We're back for a winter special episode as part of our Limit Less campaign with an activity specifically designed to get the whole family together.

"We are going to be making a Snowball Slingshot and this activity should be snow trouble at all. You are going to need a bottle like this one it needs to get narrower towards the end and have a nice wide lid, a mug or a cup, a marker pen, some sharp-ish scissors, some tape, a balloon.

"You are also going to need something to launch. I'm going to be using little scrunched up pieces of tin foil. And if you want to decorate your launcher I've got some coloured paper here and some colouring pencils to make it super festive. Take your bottle, stick it upside down in your mug, draw around the top. 

"Now use your scissors as a stabbing tool. A grown-up should definitely do this part. And now cut around your drawn line. Check the top of your bottle for jagged edges and cover them with a bit of tape.

"Now take off your lid, take your balloon and you're aiming to stretch the mouth of the balloon over the mouth of the bottle. This is quite fiddly so you might need to give your young people a bit of a hand with it. This launcher is ready to use, but I'm gonna decorate mine.

"When you have a beautifully decorated launcher like mine, take your scrunched up bit of tin foil, drop it inside your launcher, pull the balloon back, release. Maybe challenge your family and friends to a game of Snowball Slingshot. Don't shoot them at each other!

"Sam! Can I borrow you for a minute?"

Imogen switches off the camera. The action returns to the recording of Imogen and Sam playing snowball slingshot in the garden. The music is playing. On-screen text reads the current score: "Imogen 0, Sam 0". Sam launches his tin foil snowball and misses the crate. Imogen then tries and misses. We hear Sam say, "Fair enough".

Sam tries again and it lands in the crate. The on-screen text now reads: "Imogen 0, Sam 1". Imogen and Sam miss on their next attempts but then Imogen succeeds and equalises the score. We hear Sam say, "Very nice." Both Imogen and Sam high five. We hear Sam say, "Ow, my hands are freezing."

Imogen and Sam shoot one final time. Sam misses the crate but Imogen succeeds and wins the game. Imogen gasps with delight and we hear Sam mutter.

Imogen switches off the camera by the crate, and the action cuts to Imogen sitting on her own behind the table.

Imogen: "What's going on here and how can you explain it to your family? Now I won – debatably – because I know the physics behind snowball launching. The first is how the slingshot itself works. When I pull the balloon back it stretches it out of shape so that when I release it flicks into the snowball. It's this flicking force that sends the snowball flying.

"From the point that the snowball leaves the bottle the force of gravity controls the path that it takes. If I shoot straight upwards and launch the snowball starts off quickly but the downwards pull of gravity causes  it to travel slower and slower until it stops going upwards and starts to fall. 

"The snowball speeds up as it falls back down and lands exactly where it started. But because the snowball doesn't go anywhere it's not going to win you any points. If I point straight forwards then we have the opposite problem because I'm not firing upwards at all the snowball starts to fall straight away and so doesn't go very far. If I point diagonally upwards and launch instead we've got the best of both worlds. The snowball travels up and back down and takes a lovely curved path to the floor. If you want to go the furthest and get the most points you need to launch at 45 degrees. This is the angle that's in between straight up and straight forwards and this will get your snowball to go the furthest.

"Now it's totally cool if you don't get the science – as always have fun together look it up together, decorate and enjoy the game together as well. If you want to go to our Do Try This at Home website you'll find the full written up instructions for everything that I've been talking about  along with 13 other episodes for you to try out together at home.

"Thanks very much - bye bye!"

On-screen text reads: “Do Try This at Home from the Institute of Physics. For instructions and more Do Try This at Home films visit These experiments have not been specifically safety tested for home use, but we believe them to be safe if the instructions are followed. Adult supervision is recommended as appropriate. All experiments are carried out at your own risk.”